Engine Cooling Structure with Segmented Water Jacket
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Solution Overview
Problem
Existing engine cooling structures face challenges in maintaining an appropriate coolant flow rate to both the cylinder block and external coolers, leading to inefficient cooling of the combustion chamber and coolants like oil and EGR gas.
Innovation Solution
The engine cooling structure incorporates a water jacket divided by a spacer into upper and lower passages, allowing for separate control of coolant flow rates, with the upper passage directly contacting inter-bore parts and the lower passage bypassing cylinder walls to optimize coolant distribution to oil and EGR coolers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the coolant flow rate to the cylinder block is reduced to keep combustion chambers warm, then the combustion chamber temperature is improved, but the coolant flow rate to external coolers is reduced causing insufficient cooling
Solution Approach 1:
The water jacket is divided into an upper passage and a lower passage using a spacer. The upper passage supplies coolant to combustion chambers for temperature control, while the lower passage supplies coolant to external coolers (oil cooler and EGR cooler). This segmentation allows independent flow rate control for each function, resolving the contradiction between maintaining combustion chamber temperature and providing sufficient coolant to coolers.
2Device complexity
If a single water jacket is used for both cylinder block cooling and external cooler supply, then the structure is simplified, but the coolant flow rate cannot be independently controlled for each function
Solution Approach 1:
The water jacket is segmented into upper and lower passages by a spacer, enabling independent coolant flow control to different regions. The upper passage controls flow to combustion chambers while the lower passage controls flow to external coolers, providing the necessary adaptability without significantly increasing structural complexity.
Solution Approach 2:
A spacer is introduced as an intermediary component to divide the water jacket into separate passages. This spacer enables independent flow control to upper and lower regions, allowing the system to adapt to different cooling requirements while maintaining a relatively simple integrated structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables precise temperature adjustment of the combustion chamber and effective cooling of lubricants and EGR gas by optimizing coolant flow rates, preventing excessive cooling and stabilizing auto-ignition combustion.
Implementation Method 1
a coolant that circulates inside a cylinder block is led out from the cylinder block and introduced into the oil cooler and the EGR cooler
Implementation Method 2
the oil cooler and the EGR cooler cool the oil and the EGR gas with the coolant after cooling the cylinder block
Data Source
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AI summary
An engine cooling structure includes a cylinder block including a block inner peripheral wall that defines a water jacket and a block outer peripheral wall, a spacer housed in the water jacket, and a cooler provided outside the engine body. The spacer includes: a peripheral wall surrounding the block inner peripheral wall; and a dividing wall protruding from the peripheral wall to divide the water jacket into an upper passage and lower passages below the upper passage. A coolant introduced from a coolant inlet into the upper passage passes through an inter-bore part of the block inner peripheral wall. The coolant in the lower passages is introduced into the cooler through a coolant exit.